The present invention relates to heavy duty shears of the type mountable on the boom of a mobile machine such as a backhoe and, more particularly, to improvements in the structure of a shear head and the supporting structure by which the head is adapted to be mounted on the boom.
Heavy duty shears of the type to which the improvements of the present invention are directed are well known in conjunction with the handling and shearing of a wide variety of scrap materials including, for example, iron and steel pipes of various diameters, iron and steel solid rod of various cross-sections and diameters, structural beams such as I-beams, channels and angles, as well as a variety of other metallic and non-metallic materials and material configurations. Generally, the shear head includes a supporting structure by which the head is adapted to be attached to the boom of a mobile machine, such as a backhoe, and the shearing components are relatively pivotal and powered by a hydraulic piston and cylinder arrangement which is actuated through the hydraulic system of the machine. Various prior art shears of the foregoing character are illustrated, for example, in U.S. Pat. No. 4,519,135 to LaBounty; U.S. Pat. No. 4,450,625 to Ramun et al; U.S. Pat. No. 4,558,515 to LaBounty; U.S. Pat. No. 4,616,417 to Gross; U.S. Pat. No. 4,670,983 to Ramun et al; U.S. Pat. No. 4,686,767 to Ramun et al; U.S. Pat. No. 4,719,975 to LaBounty; and U.S. Pat. No. 4,908,946 to LaBounty.
While the foregoing and other shears heretofore available are operative for their intended purposes, there are a number of disadvantages attendant to the manufacture, structure and maintenance thereof which result in the devices being difficult and expensive to construct and to maintain. Moreover, such disadvantages affect the efficiency of operation of the shear and the life of component parts thereof and, especially in connection with maintenance, make it extremely difficult and expensive, and impossible in certain circumstances, to perform maintenance on the apparatus in the field. All of these disadvantages add to the cost of construction, operating and maintaining the apparatus.